Conventionally, a toner supply unit that is described in Patent Literature 1 (Japanese Patent Application Laid-open No. 2005-178810) is known as a toner supply unit that is used in this type of image forming apparatus. FIG. 54 is a cross-sectional view that illustrates a head section of a toner container that is attached to the toner supply unit described in Patent Literature 1. Although a toner container 900 is formed into a cylindrical shape, this figure illustrates only the container head section that is the end section of the cylindrical toner container 900 in the direction of a cylinder axis line. The container head section of the toner container 900 is connected to a lid member 901 that closes a toner discharge opening that is provided on the container head section. An undepicted toner supply unit holds the cylindrical toner container 900 in a position such that the direction of the cylinder axis line of the toner container 900 extends in a horizontal direction. As illustrated in FIG. 55, the toner supply unit, which holds the toner container 900, holds a handle section 901a by using a lid pulling mechanism 950, the handle section 901a protruding from the front surface of the lid member 901 of the toner container 900. Then, the lid pulling mechanism 950 moves in a direction away from the toner container 900 along the direction of the cylinder axis line of the toner container 900 so that the lid member 901 is pulled out of the container head section of the toner container 900 as illustrated in the drawing, whereby the toner discharge opening is opened. Thus, a gap is formed between the toner discharge opening and the lid member 901 that is pulled out of the container head section. In this state, the toner container 900 is rotated about the cylinder axis line of the toner container 900. In accordance with the rotation, toner in the container is moved from the container rear end section side toward the container head section due to an effect of a helical protrusion that is provided on the inner peripheral surface of the toner container 900, whereby the discharge of toner through the toner discharge opening is facilitated. The toner discharged through the toner discharge opening is conveyed by an undepicted conveying unit and is supplied to a developing apparatus.
With the toner supply unit that have the above configuration, as illustrated in FIG. 55, after toner is discharged through the toner discharge opening, the discharged toner passes through, out of the entire area of the gap formed between the toner discharge opening and the lid member 901, an area of the lower end section in a vertical direction. Contrary to this, no toner passes through an area of the upper end section of the gap in a vertical direction; therefore, a space is formed therein. While the toner container 900 is driven to rotate, air passes through the space as indicated by the arrow in the drawing, and the air outside the container is easily taken in through the toner discharge opening. Thus, there is a possibility that the taken air blows the toner in the container and the spread of toner from the inside of the container to the outside thereof is facilitated.
Even if the toner container 900 is not configured to be driven to rotate, there is a possibility that toner is spread in the similar manner if a configuration is such that the toner discharge opening faces lateral to the container as illustrated in the drawing. For example, if the image forming apparatus has a configuration for driving and rotating a conveying member that conveys toner, although the toner container 900 is not driven to rotate, there is a possibility that air is taken in the container through the above-described space due to the driving and rotating of the conveying member and the toner is spread around. Furthermore, for example, if a moderate air current is generated from above toward below the apparatus due to driving of an exhaust air fan, or the like, there is a possibility that the air current enters the container through the toner discharge opening that faces lateral to the container, as indicated by the arrow in FIG. 55, and toner is spread around. If a configuration is such that the toner container is set in the toner supply unit in a position such that the toner discharge opening faces lateral to the container, there is a possibility that toner is spread around in a similar manner.
The present invention is made in consideration of the above problem and has an object to provide the following image forming apparatus and toner container. Specifically, it is an image forming apparatus, or the like, that can prevent the occurrence of spread of toner from the inside of the toner container to the outside thereof, the toner container being held by a toner supply unit in a position such that a toner discharge opening faces lateral to the container.